Method of and apparatus for producing sheet glass



Dec. 20,- 1932. E. DANNER ,8 7

METHOD OF AND APPARATUS FOR PRODUCING SHEET GLASS Filed Dec. 1, 1924 I12 Sheets-Sheet 1 gwuento z I Dec. 20, 1932. E DA NNER 1,891,372

METHOD OF AND APPARATUS FOR PRODUCING SHEET GLASS Filed Dec. 1, 1924 12 Sheets-Sheet 2 l l 'l Dec. 20, 1932. BANNER 1,891,372

METHOD OF AND APPARATUS FOR PRODUCING SHEET GLASS File d Dec. 1, 1924 1 12 Sheets-Sheet 4 Dec. 20, 1932. N R 1,891,372

METHOD OF AND APPARATUS FOR PRODUCING SHEET GLASS Filed Dec. 1, 1924 12 Sheets-Sheet 5 .Dec. 20, 1932.

E. 'DANNER 1,891,372

METHOD OF AND APPARATUS FOR PRODUCING SHEET GLASS Filed Dec. 1, 1924 12 Sheets-Sheet 6 Dec. 20, 1932.

E. DANNER METHOD OF AND APPARATUS FOR PRODUCING SHEET GLASS Filed Dec. 1, 1924 12 Sheets-Sheet 7 Dc. 20, 1932. E. DANNER 1,891,372

METHOD OF AND APPARATUS FOR PRODUCING SHEET GLASS Filed Dec. 1, 1924 12 Sheets-Sheet 8 TTE 1U @321 yw n METHOD OF E. DAN NER Filed Dec. 1, 1924 AND APPARATUS FOR PRODUCING SHEET GLASS 12 Sheets-Sheet 9 Dec. 20, 1932. E. BANNER 1,891,372 I METHOD OF AND APPARATUS FOR PRODUCING SHEET GLASS Filed Dec. 1, 1924 12 Sheets$heet 10 A A i Dec. 20, 1932. E. DANNER METHOD OF ANDAPPARATUS FOR PRODUCING SHEET GLASS Filed Dec. 1, 1924 J 1 L L 12 Sheets-Sheet ll gwuento'o s51, mom 6n an Va;

Dec. 20, 1932;

METHOD OF AND APPARATUS FOR l RODUClNG SHEET GLASS E. DANNER Filed Dec. 1, 1324 12 Sheets-Sheet 12 Patented Dee. 2:0,.1932

} J UNITE-ESTATES PATENT orrlcr.

EDWARD BANNER, OF NEWARK, OHIO METHOD OF AND APPARATUS Application filed December and apparatus by which the glass is flowed onto a slab below its top and radiantheat is applied to the films of glass as they flow downward over the slab.- The detailsand minor objects of my invention will appear as the desorption proceeds.

In the accompanying drawings, Figure 1 is a vertical section of a furnace embodying my invention taken -on the line 1-1 of Fig. 2; Fig. 2 is a vertical sect on taken on the line 2 2 of Fig. 1;Figs. 3 and 4 are cross sections taken on the lines 3-3 and 44, respectively, of Fig. 2; Fig. 5 is a horizontal section on the l ne 5- 5 of Fig. 4; Fig. 6

I is a horizontal section on the line 66 of- Fig. 3, parts being broken away; Fig. 7 is a vertical section on the line 77 of Fig. 6;

Fig. 8 s a section on the line 88 of Fig. 7;

Fig. 9 is a section on the line 99 of Fig. 2;

Figs..1O and 11 are sections on the lines 10 10 and, 11,-11, respectively of Fig. 6; Fig.

12 is a, horizontal sect on of a modified form of forehearth;'Fig. 13 is a. side view of a sheet-forming slab; Fig. 14 is a vertical sec tion on the line;1414 of Fig. 13; Fig. 15

s a horizontal section on the line 1515 of Fig. 13; Fig. 16 is an enlarged detail of the lower portion shown in Fig. 14; Fig. 17 is an enlarged detail of the anchor plate; Fig.

18 is an elevation of an alternative form of slab: F g. 19 is a section on the line 19-19 of Fig. 18: Fig. 20 is a section on the line 20-20 of Fig. 18; Fig. 21 is an enlarged detail of *an alternative form of anchor plate; Fig. 22 is an enlarged detail showing the form of the discharge slot; Fig. 23 is a section showing an alternative form of discharge slot;

In front of the discharge orifice of the usual 0 tank furnace 30 I position a forehearth 31.

FOR PRODUCING SHEET GLASS 1, 1924. Serial No. 753,034.

The forehearth may be supported in various ways, but the supporting means I have shown comprises/vertical columns 32 supporting cross beams 33, which in turn support longitudinal beams 34. The spaces between the beams 34 are filled in by blocks 35, except for spaces which are left open for reasons which will be stated later. Above the filling blocks and beams there is a foundation of brick 36 which are preferably insulating brick, and above these is the floor of the forehearth constructed of blocks 37 of the usual material used for that purpose.

Above supporting columns 32 are columns 38 on the sides of the forehearth, and an upper framework 39 is mounted upon the upper end of these columns, and side and end framework 40 is attached to the forehearth supporting beams and the upper framework. The sides of the forehearth are likewise preferably provided with outside insulating brick 41 and inner fire-clay blocks 42. Along the sides and outer end of the forehearth there are provided inner Wall tile 43. Between these tile and the wall blocks are spacer blocks 44, so that insulating space 45 is provided between the tile and the wall blocks.

In the preferred form, the end of the forehearth next to the tank furnace is divided into three longitudinal compartments by partition blocks 46. Splice blocks 47 are placed in the outlet opening of the tank furnace and project over floor blocks 37 of the forehearth, and similar splice blocks 48 are arranged at the sides of the tank opening. Roof beams 49 rest upon the side walls and partitions of the forehearth and carry roof tile 50.

The openings from the tank into the several compartments of the forehearth are provided with gates, each formed of a plurality of blocks 51. v Over these gates are provided cross-heads 52, 53 and 54, the cross-heads 52 and 54 being approximately the width of the side openings and 53 being approximately the width of the center opening. Hand-wheels 55 56 and 57 are provided for the respective cross-heads 52, 53 and 54. Each hand-wheel operates a cross-head, and cables 58 pass from the cross-heads over pulleys 59 and 60 to the blocks of the respective gates, at turn-buckle 61 being interposed in the cable above each block in order that the position of the several blocks with relation to each other may be adjusted, as desired.

Between the roof of the forehearth and the front and rear sides of this opening are covered by blocks 67 which rest upon the floor blocks and extend partially over the opening. Blocks 67 are held in position by keys 68 between them and-the floor blocks upon which they rest. Lip blocks 69 are provided upon the edges of blocks 67 towards the slot, and preferably the rear sides of these lip blocks are rounded at 70 and enter curved grooves in blocks 67, so that the lip blocks are substantially hinged on blocks 67.

The outer end of the well, or the end farthest distant from the tank. furnace, is substantially closed by gate blocks 71, which are suspended from cables 72, which pass over pulleys 73 and 7 4 mounted on the upper framework, and thence down to a cross-head operated by an adjusting hand-wheel 75. The relative positions of blocks 71 may be conveniently adjusted by adjusting the connections of the cables with the cross-head. Inner gate blocks 76 form a partition between the well and the central compartment of the forehearth. These blocks are provided with openings 77 and are suspended from cables 78, which pass over pulleys 79 and 80 on the upper framework to a cross-head operated by an adjusting hand-wheel 81.

A flow-controlling or sheet-forming slab 82 is suspended in position to receive the glass flowing over the lip blocks and downward between them. The slab is constructed with a metallic discharging edge 83 formed of a material, such-as nichrome, which will not discolor molten glass flowing thereover. This edge is suspended by rods 84 from a beam 85, nuts 86 on the upper ends of the rods resting on the upper side of this beam.

Above the slab edge there are wedging blocks 87 havin their lower ends substantiall the width of the metallic edge member, and their upper ends somewhat thicker. These slab blocks are provided on their ends with grooves 88 which fit over rods 84, so as to present a continuous surface on each side of the slab. Anchor plates 89 are provided with holes 90, which fit over the suspending rods tion, the cross section of the slab has a shape similar to that of an arrow-head with the shaft of the arrow between the li blocks.

'Beam 85, which supports the sla is referably constructed of two channel mem ers 93 with their flanges outward, so that there is provided between them a slot 94 throu h which the slab-supporting rods project. t the ends of this slot, there are filler blocks 95 which are attached to the channel members. The filler blocks are provided with holes 96 to which elevating means may be attached, when it is desired to remove the beam and its supported slab.

Each end of this composite beam 85 is supported in an end frame 97 having an upright member 98 on each side of the beam. Supported on .each side of the well is a bed plate 99 upon which one of the end frames rests, and each bed plate is provided with a lug 100 on each side of its respective end frame, and set screws 101 passing through these lugs fix the end frames in adjusted position laterally. There is a threaded member 102 positioned beneath the filler block 95 and the ends of channel members 93 at each end of the beam, and a set screw 103 passing through the .threaded member and resting on the bed plate adjusts the end of the beam vertically.

Between the sides and the end gates of the well there are roof beams 104, similar to roof beams 49 and carrying similar roof tile 105, which form the major portion of the roof of the well. Immediately over the slab there are blocks 106 between the slab supporting rods. These blocks might rest upon the slab blocks, but they are shown as being provided with lugs 107 attached to books 108, which pass upward through slot 99 and have nuts 109 resting upon the top of the beam, so that blocks 106 are supported directly from the beam and do not rest upon the lower slab blocks. Blocks 106 may contact blocks 92 and form in effect a continuation of the slab, or they may be elevated and used asadjustable gate blocks above the slab, or as roof blocks.

Between the roof blocks and blocks 106 there are filling pieces 110, which rest loosely upon the roof blocks so that they close the roof of the well, but do not interfere with the adjustment of the slab or with its remova1, when desired, and furthermore, furnish means of access to the well, when desired.

Blocks 110 may be arranged to leave slots between them and block 106, if such slots are desired for cooling or other purposes.

I have shown burners 111 in position to direct flame through openings 77 into the central compartment of the forehearth towards the tank, similar burners 112 are provided for directing flame into the front end of the forehearth towards gate blocks 71, and burners 113 are provided at the front end of the forehearth in position to direct flames down the side channels of the forehearth.

Beneath the well, I provide means for governing the temperature of the glass flowing down the slab. For this purpose I provide casing members 114 supported in any desired manner upon the fixed framework ofthe forehearth. Within this casing are lining blocks 115. At the lower side of the slot, between these casing members, burners 116 are provided with flared ends 117. Slanting heat-controlling blocks 118 are-provided immediately above these burners in position to spread the flames so as to form a practically continuous sheet of flame on each side of the slab.

A burner 119 is provided for separately controlling the heat at each end of the slab. Holes 120 are formed in the lower part of the casing and lining blocks so as to admit flame from burners 121. Thin tile 122, which readily transmit heat, rest upon the lower lining brick and support the edges of blocks 67. These thin tile, which may be called'cup tile, are provided with strengthening ribs when necessary. The tile shown are reversible, so-

that either side may be placed towards the slab, as desired. A combustion chamber is provided between the lining block and cup tile 122 which prevent the direct contact of the flame from burners 121 with the glass flowing over the slab. A peep hole 123 is provided for inspection of the action of the flame, said holes being normally closed by plugs 124.

At each end of the combustion chamber formed by the cup tile and the lining blocks, there is a channel block 125 provided with a channel 126 opening-into this space. Between the blocks 125, at each end of the tile, there is an end channel block 127 having a channel 128 opening at its ends into channels 126 and with itsupper side opening out into the space immediately surrounding the slab. The inner lower corner of each side block 66 is beveled off at the several points 129 to allow communication between channels 126 and 128 and the adjacent chambers.

' A damper 130 is provided for controlling the communication between the space surrounding the slab and each channel 128, the position of the damper being readily controlled through a rod 131. Through the upper edges of the lining blocks on each side of i the channel there are draft openings 132 controlled by dampers 133. Each damper 133 has a downwardly extending stem 134 provided with a rack which'is 1n mesh with a pinion 135. The pinions on each side of the slab are mounted on a rod 136, the rod being extended and controlled by a handle in any desired position.

Flues 137 lead forward from the draft openings towards the outer end of the furnace and connect with cross-flues 138, which lead to longitudinal flues 139, running backward to cross-flues 140 near the rear end of the forehearth. The draft openings towards the rear side of a forehearth open into flues 141, which lead directly backward to cross-flues 142 adj acent the flues 140.

Over the rear end of the forehearth, there is arranged a smoke-box 143. Vertical flues 144 lead upward from the side compartments of the forehearth into the underside of :this smoke-box, while middle flues 145 lead up from the central compartment of the forehearth into the smoke-box. Each of the flues 144 and one of the flues 145 is supported by a rod 146 connected to its upper end and passing upward through the box and through a crosspiece 147 resting on the top of the box and held in adjusted position by a nut 148 on its upper end. A chimney flue 149 leads upward from the smoke-box and is positioned slightly at one side of the center thereof and comes over one of the fines 145. This flue 145 is supported by a rod 150 connected to a cross-head 151, which in turn is supported by rods 152 passing through the upper wall of the box and crosspieces 153 on top of the box and held in adjusted position by nuts 154.

The ends of flues 140 and 142 connect with vertical flues 155, one on each side of the forehearth, and slanting flues 156 lead from the upper ends of these vertical flues into the ends' of smoke-box 143.

As will be seen from an inspection of the drawings, longitudinal flues 137, 139 and 141 are located between the longitudinal beams which support the floor of the forehearth and are held in position between these spacer blocks 157. By positioning the longitudinal flues in this manner, I avoid inter fering with the headroom beneath the forehearth, and the flues 137 are continued to the front end of the forehearth, so that cross-flues beams by 1 mediately adjacent the sheet-forming point.

The central longitudinal beams are slightly spaced apart by blocks 158.

As will be seen, the structure is such that lip blocks 69 are elevated above the floor of the main part of the forehearth, and the upper portion of the combustion chamber back of the .cup tiles is extended upward through the level of the floor of the'main part of the forehearth. In order to lead the products of combustion from the upper portion of these chambers downward to the longitudinal fines, blocks 159 are provided with downwardly slanting passageways 160.

The usual expansion joints 161 are provided between the blocks forming the lining 5 of the forehearth, and the structure is such that these blocks may expand without exerting compressing action upon the walls of the well. Metallic plates 162 are provided at various points in order to enable the blocks to expand and move along with respect to the ing blocks within the casing, and their lower ends fit within the casing, so that they are held rigidly in position. Blocks 66 are held a fixed distance apart by the blocks between them.

The upper edges 163 of the casing members enter grooves 164 in floor blocks 37 ad-.

jacent the slot, so that these blocks. are held rigidly in position, and are prevented from being crowded towards each other by expansion of surrounding floor blocks. In this way the various blocks comprising the well areheld in fixed relation to each other, and the well is constructed to withstand any pressure which will be exerted upon it by the expansion of surrounding floor blocks.

I prefer to allow the glass to entirely surround the slab and flow down its edges as well as its sides, and therefore construct the slab so as to leave a space between its edges and blocks 66. I provide grooves 165 in the blocks to furnish additional space between the blocks and slab above the glass level and allow the positioning and adjustment of blocks 166 which rest upon the bottoms of these grooves between the ends of lip blocks 69 and accurately gauge the slot at the end of the slab. Blocks 166 are provided with stems 166 to aid in their manipulation. \Vhen desired, blocks 166 may be adjusted towards or from the slab, or they may be removed and similar blocks of a different size inserted.

By the use of these blocks the thickness of the films of glass flowing down the edges of the slab may be controlled, and the temperature of these films may be controlled by the separate burners provided therefor, so that the edge films will properly perform their function of maintaining the width of the sheet and producing proper edges therefor.

As will be seen from an inspection of Figs. 13 and 15, the end blocks of the slab are provided with holes 167 and threaded on the end rods 84. so that the material 168 of the blocks covers the rods at the ends and prevents the access of glass or flame to the rods. It is inconvenientto form holes through slabs, and

therefore I usually groove the blocks deeply and fill in the outer portions of the grooves at 168, in order to give the slab the desired final form.

The upper surfaces of blocks 87 extend beyond the blocks 92 and provide ledges 169 which will contact the films of glass for a purpose which will be described later, but under some circumstances this action is not required so that the alternative form of slab 170, shown in Figs. 18 and 19, may be used. In this form of slaban edge member 171 is used, supported by rods 172 corresponding to the similar parts in the preferred form of slab; but the lower blocks 173, instead of being wedging, merely round out from the lower edge member until they are of sufficient thickness and then are of even thickness throughout, and the upper slab members 174 are of this even thickness, so that the sides of the slab are vertical from the place where the glass contacts therewith down to adjacent the lower edge. Where these thinner slabs are used, anchor plates 175 are corre spondingly modified in form, as shown in Fig. 21.

In both forms of slab illustrated, the sections are supported upon the metallic edge member and are held inplace by the anchor plates and suspension rods. Where desired, the upper sections of the slab may be suspended separately, in the manner in which blocks 106 are suspended, and the slab might be divided into vertical sections only, and each Is)ection suitably suspended by metallic memers.

The edges of lip blocks 69 may be square, but I prefer to round off their lower edges 176, as shown in Fig. 22. When this is done the glass follows the curve for a certain distance and then pulls away from the surface of the block at an angle materially greater than 90. This widening of the slot tends to lessen the danger of streaks on the surface of the glass leaving the block. Under some circumstances it is preferable to end the curved portion of the slab at a definite line 177, as shown in Fig. 23.

After the glass leaves the lower end of the slab, it asses vertically downward between rollers 1 8. It is desirable to have the glass comparatively cool before it is contacted by rollers, and, in order to avoid placing the rollers at too great a distance from the slab or having too considerable weight of glass between the slab and the rollers, cooling members 179 may be provided between the slab and the.rollers. In the form shown, these cooling members are designed to be filled with water.

Peep holes (not shown) are provided for observation through the walls of the forehearth in the customary manner. For observation of the middle compartment of the forehearth I provide removable blocks 181 over burners 111. These removable blocks 181 are provided with upstanding members 182 by which they may be raised or removed, when desired, for observation of the middle compartment of the forehearth, the under surface 183 of the block 'next to the gate blocks 76 being beveled to facilitate this observation. Blocks 181 may be adjustably supported in any suitable manner to regulate the size of openings above the burners, and, if desired, the use of the burners may be discontinued at times and the regulable openings used for cooling.

While I prefer to divide the forehearth longitudinally by partition blocks 46, as indicated in Fig. 5, these blocks may be removed, if desired, as shown in Fig. 12, in which case the roof supporting beams must be extended from one side of the forehearth to the other at the rear end of the forehearth behind the well.

The manner of using the apparatus thus far described will be fairly apparent from the foregoing description, but it may be briefly summarized as follows:

Glass is melted and refined in the usual manner within the tank 30 and fiows from there beneath the gate members into the forehearth. Ordinarily, these gate members are elevated, as shown in Fig. 2, so that they do not contact the glass, but where desired for any reason they may be lowered into contact with the upper surface of the glass and, if desired, the several blocks may be adjusted to different elevations. The glass flowing through the middle gate passes directly to the rear side of the suspended slab. Burners 111 are operated to furnish the desired amount of heat so that the glass will reach the slab at proper temperature. Due to the comparative elevation of blocks 69 there is a considerable depth of glass over the floor of the forehearth, and for this reason the flow of the glass through the compartment is comparatively slow, and time is afforded for properly tempering the stream before it reaches the slab.

Glass flowing through the side gates passes between the partition walls and the inner side walls to the front end of the hearth and thence beneath gate 71 to the outer side of the slab. Burners 112 and 113 are operated so that the glass will be at the proper temperature when it reaches the slab; because of the differences between the path of glass followed by the stream flowing to one side of the slab and that flowing to the other side of the slab, separate control of the temperatures in the central compartment and in the side compartments is desirable, and the upward extension of the slab, which divides not only the streams of glass but the space above the glass and below the roof, aids this separate control of the temperature.

The inner blocks 43 along the sides and end of the forehearth are particularly advantageous when streams 0 glass are to be flowed along the sides and around the front end of the hearth, because they leave the insulating space between them and the side walls proper of the forehearth. Even where molten glass leaks through the joints and fills or partially fills the space between blocks 42 and blocks 43 the effect of these inner blocks is not lost, because these pockets full of glass also act as insulators, and if the glass in these pockets does become devitrified it does not injure the product, because it does not mix with the flowing stream of molten glass. The glass contacting the inner surfaces of blocks 43 remains at substantially the same temperature as the other glass in the stream, re-

sulting in a stream of uniform glass.

Ordinarily, I prefer to flow the glass onto the two sides of the slab in substantially the same condition, but where differential treatment of the two films of glass is desired this construction allows it to be carried out readily.

The ass flows down the opposite sides of the sla as will be readily apparent, and unites along the lower edge in a sheet 180 which passes from this point downward to the rollers 17 8 and is carried off and further treated in any desired manner. The treatment of the glass as it flows down the sides of the slab is dependent to some extent upon the temperature of the glass when it reaches the slab, the thickness of the sheet being formed, the nature of the glass and the effect I desired. While 1 have shown means for heating the lower end of the films by a directly applied flame and the upper portion of the films by heat radiated from cup tile 122, very little application of heat is required in the ordinary use of this apparatus, and sometimes dooling is desirable. Members 121 are referred to as burners, but it will be readily understood that, where desired, cooling air may be introduced through these members, so that the heat radiated from the films of glass flowing down the sides of the slab will be rapidly absorbed by the cup tile. In other words, these chambers back of the tile may be used so that the tile will become either heating or cooling members, as desired.

One purpose of ledges 169 is to smooth out any irregularities or streaks which may occur in the films flowing downward from the slots between the slab and the lip blocks. As will be readily apparent, the glass has a tendency to pile up on these ledges and relieve the surface strains or streaks at that point, and, when it is again drawn away in films over the edges of the slab, irregularities are smoothed out. I

Another use of the ledges is to regulate the flow of glass. The downward flow of' glass through the slots is retarded by raising the slab and bringing the ledges adjacent the slots. Lowering the slab lessens the retardin influence of the ledges.

he slab supporting beam is mounted so that either end or both ends may be adjusted laterally, as desired, one end may be raised or lowered as necessary to make the slab hang correctly, and both ends may be raised or lowered to raise or lower the slab, either to adjust the relation of the ledges to the slab or to adjust the distance between the slot and the discharge edge of the slab.

The flames from the burners 116 are spread out by the blocks 118, so that they form substantially one continuous flame on each side of the slab, and this flame, applied along the film of glass as it is leaving the slab, may be used to heat the surface of the glass at this point and give an added fire-finish to the surface. Furthermore, the space between the glass and these blocks is quite restricted, and the temperature of the chamber surrounding the slab is controlled, not only by controlling the temperature of the chambers back of the cup tile, but by directly controlling the flow of gases through this chamber. As will be readily seen, proper regulation of the burners 116 and dampers 130 will give the desired rate of movement of gases through the chamber surrounding the slab.

When the dampers are closed there can be but little flow of gases through the slot between the films and blocks, so that the flames from burners 116 will impinge upon the films along a well defined line and will not play upward along the surface of the films to any considerable amount. In this way the firefinishing action can be confined to a comparatively narrow section of the film.

If it is desired, cooling air instead of fuel gases may be discharged through members 116.

When repair of the slab is necessai y for any reason, cover blocks 110 may be slid to one side and the beam supporting the slab raised by any suitable means, lip blocks 69 turning on their rounded edges 70 as upon hinges. The slab may be repaired and replaced or, if desired, another slab may be lowered into position and the operation of the furnace continued while the first slab is being repaired. The removable members 110 furnish a convenient means for observing the action of the glass adjacent the slabs and furnish access to this portion of the forehearth whenever it is desired, as well as providing adjustable cooling openings when desired.

It will be readily observed from the above disclosure that I have provided an apparatus and method wherein the glass is flowed onto a slab below its upper end so that the glass flowing onto the two sides of the slab is separated before it reaches the slab and, furthermore, the glass flowing downward over the slab may be subjected to radiant heat from the cup tile and its temperature controlled in this way without subjecting its 1 surface at this point to the direct action of flame. Furthermore, both the thickness and temperature of the glass flowing downthe edges of the tile may be separately controlled so that the desired formation may be given to the edges of the glass sheet.

While I have shown the construction and operation of one form of my apparatus in considerable detail, it will be understood that various changes may be made within the scope of the appended claims.

What I claim is:

1. In apparatus of the character described, a glass tank furnace, a forehearth connected with the furnace, a well in the forehearth having an opening in its bottom, partitions in the forehearth dividing the glass flowing from the tank into a middle stream flowing to the side of the well towards the tank and side streams flowing along the side and end of the forehearth to the other side of the well, and a supplementary side wall spaced inward ly from the main side wall of the forehearth and forming an outer limit for the stream of glass flowing along the side of the forehearth.

2. In apparatus of the character described, a glass tank furnace, a forehearth connected to said furnace to receive glass therefrom, a well in the forehearth having a slot in its bottom, a slab in the well passing through the slot and extending beneath the floor of the forehearth and upward above the normal level of the glass in the forehearth.

3. In apparatus of the character described, a glass tank furnace, a forehearth connected to said furnace to receive glass therefrom, a well in the forehearth having a slot in its bottom, a slab in the well passing through the slot and extending to the roof of the well.

4. In apparatus of the character described, a glass tank furnace, a forehearth connected to said furnace to receive glass therefrom, a well in the forehearth having a slot in its bottom, a slab in the well passing through the slot and extending to the roof of the well, and separate means for controlling the temperature of the glass on the two sides of the slab.

5. In apparatus of the character described, a glass tank furnace, a forehearth connected to said furnace to receive glass therefrom, awell in the forehearth having a slot in its bottom, a slab in the well passing through the slot and extending to the roof of the well, the well having end walls at the ends of the slab and being provided with gates above the glass on the two sides of the slab.

6. In apparatus of the character described, a glass tank furnace, a forehearth connected tosaid furnace to receive glass therefrom, a well in the forehearth having a slot in its bottom, a slab in the well passing through the slot and extending to the roof of the well, the well having end walls at the ends of the slab and being provided with gates above the glass on the two sides of the slab, said gates being composed of separately adjustable blocks. i

7. In apparatus of the character described, a glass tank furnace, a forehearth connected to said furnace to receive glass therefrom, a well in the forehearth having a slot in its bottom, a slab in the well passing through the slot and extending to the roof of'the well, the well having end walls at the ends of the slab and being provided with gates above the glass on the two sides of the slab, and separate means for controlling the heat of the glass approaching the two sides of the slab.

8. In apparatus of the character described, a glass tank furnace, a forehearth connected to said furnace to receive glass therefrom, a well in the forehearth having a slot in its bottom, a slab in the well passing through the slot and extending to the roof of the well, and separate means for controlling the temperature of the glass on the two sides of the slab, the well being provided with end walls at the two ends'of the slab and there being partitions in the forehearth dividing the glas flowing from the tank into a central stream flowing to one side of the slab and side streams flowing along the sides and front of the tank to the other side of the slab.

9. In apparatus of the character described, a glass tank furnace, a forehearth connected to said furnace to receive glass therefrom, a well in the forehearth having a slot in its bottom, a slab in the well passing through the slot and extending to the roof of the well, and separate means for controlling the temperature of the glass on the two side of the slab, the well being provided with end walls at the two ends of the slab and there being partitions in the forehearth dividing the glass flowing from the tank into a central stream flowing to one side of the slab and side streams flowing along the sides and front of the tank to the other side of the slab, and separate means to control the glass flowing to the opposite sides of the slab.

10. In apparatus of the character described, a glass tank furnace, a forehearth connected to said furnace to receive glass therefrom, a well in the forehearth having a slot in its bottom, a slab in the well passing through the slot and extending to the roof of the well, and separate means for controlling the temperature of the glass on the two sides of the slab, the well being provided with end walls at the two ends of the slab and there being partitions in the forehearth dividing the glass flowing from the tank into a central stream flowing to one side of the slab and side streams flowing along the sides and front of the tank to the other side of the slab, there being an inner wall spaced from the main side wall of the forehearth and forming an outer limit for the stream of glass along the side of the forehearth.

11. In apparatus of the character described, aglass tank furnace, a forehearth connected to said furnace to receive glass therefrom, a well in the forehearth having a slot in its bottom, a slab in the well passing through the slot and extending to the roof of the well, and separate means for controlling the temperature of the glass on the two sides of the slab, the well being provided with end walls at the two ends of the slab and there being partitions in the forehearth dividing the glass flowing from the tank into a central stream flowing to one side of the slab and side streams flowing along the sides and front of the tank to the other side of the slab, and a gate composed of separately adjustable blocks on each side of the slab.

12. Inapparatus of the character described, a glass tank furnace, a forehearth connected to said furnace to receive glass therefrom, a well in the forehearth having a slot in its bottom, a slab in the well passing through the slot and extending to the roof of the well, and separate means for controlling the temperature of the glass on the two sides of the slab, the well being provided with end walls at the two ends of the slab and there being partitions in the forehearth dividing the glass flowing from the tank into a central stream flowing to one side of the slab and side streams flowing along the sides and front of the tank to the other side of the slab, and gates composed of separately adjustable blocks at the entrance point from the tank into the middle stream and side streams of the forehearth.

13. In sheet glass drawing apparatus, a container for molten glass having a slot in its bottom and a slab passing through the slot and adapted to receive a film of glass on each side thereof, said slab extending downward below the floor of'the container and upward above the normal level of the glass in the container. 7

let. In apparatus for forming sheet glass, a container for molten glass having a slot in its bottom and a slab extending through the slot and substantially dividing the glass in the container on one side of the slot from that on the other side thereof and extending downward beneath the bottom of the container.

15. In sheet glass drawing apparatus, a forehearth for containing molten glass, a well in the forehearth having a slotted roof and a slotted floor, a slab extending through said slots and projecting beneath the floor of the forehearth.

16. In sheet glass drawing apparatus, a forehearth for containing molten glass, a Well in the forehearth having a slotted roof and a slotted floor, a slab projecting through saidslots, the floor of the well on the sides of the slot being raised above the level of the floor of the forehearth.

17. In sheet glass forming apparatus, a container for molten glass having a slot in its bottom, the floor of the container being raised on the two sides of the slot, a slab in pos'tion to receive glass flowing through the slot, and tempering chambers on the two sides of the slab, the upper portions of said chambers extending upward to approximately the main level of the floor of the container.

18. In sheet glass forming apparatus, a container for molten glass having a slot in its bottom, the floor of the container being raised on the two sides of the slot, a slab in position to receive glass flowing through the slot, tempering chambers on the two sides of the slab, the upper portions of said chambers extending upward to approximately the main level of the floor of the container, and flues adapted to carry away gases from the tops of said tempering chambers.

19. In sheet glass forming apparatus, a container for molten glass having a slot in its bottom, the floor of the container being raised on the two sides of the slot, a slab in position to receive glass flowing through the slot, tempering chambers on the two sides of the slab, the upper portions of said chambers extending upward to approximately the main level of the floor of the container, and flues for carrying off tempering gases connected to the tops of said tempering cham-v bers and slanting downward to a level beneath the floor of the container.

20. In apparatus for forming glassware,-

a receptacle for containing molten glass and having a discharge opening in its bottom, beams supporting the receptacle, means to supply currents of gases to control the temperature of glass flowing downward through said opening, and flues between said beams for carrying off the, tempering gases.

21. In apparatus for form ng glassware, a container for molten glass having an opening in its bottom, tempering chambers surrounding the glass flowing through the opening, beams supporting the container and flues between the beams for carrying off gases from the tempering chambers.

22. In apparatus for forming sheet glass, a conta ner for molten glass having a slot in its bottom, a slab projecting downward from said slot and adapted to receive on its two sides films of glass flowing through said slot,

a chamber surrounding said slab, burnersv arranged in a row on each side of the slab at the bottom of said chamber, and flamespreading lips above said burners.

23. In apparatus for forming sheet glass, a containerfor molten glass having a slot in its bottom, a slab extending downward from said slot and adapted to receive on its two sides films of glass flowing through said slot, a tempering chamber surrounding said slab, fiues for carrying away. tempering gases from said chamber, dampers controlling said flues, burners arranged in a row on 'each side of the slab at the bottom of said 25. In apparatus for forming sheet glass,-

a container for molten glass having a slot in its floor and a slab entering the slot and extending therebelow, the slab increasing in thickness below the floor of the container and then thinning to an edge to its bottom.

26. In apparatus for forming sheet glass, a container for molten glass having a slot in its floor and a slab having an upper portion thinner than and positioned in the slot and a lower portion thicker than and positioned below the slot.

27. In apparatus for forming sheet glass, a container for molten glass having a slot in its roof and a slot in its floor, and a slab extending through said slots and projecting beneath the floor of the container.

28. In apparatus for forming sheet glass, a container for molten glass having a slot in its roof and in its floor, a slab extending through said slots and suspended from the roof of said container.

29. In apparatus for forming sheet glass, a container for molten glass having slots in its roof and floor, a slab extending through said slots, said slab being arrow-shaped in cross section with the shank of the arrow extending through both slots and the head of the arrow pointing downward beneath the floor of the container.

30. In apparatus for forming sheet glass, a container for molten glass having slots in its roof and floor, a slab extending through said slots, said slab being arrow-shaped in cross sect-ion with the shank of the arrow extending through both slots and the head of the arrow pointing downward beneath the floor of the container, said slab being sus pended from above;

31. In apparatus for forming sheet glass, a container for molten glass having slots in its roof and floor, a slab extending through said slots, said slab being arrow-shaped in cross section with the shank of the arrow extending through both slots and the head of the arrow pointing downward beneath the floor of the container, said slab being sus- 

